It may only be a large rock, but images like this drive home the significance of the HiRISE instrument on board NASA’s Mars Reconnaissance Orbiter; it enables us to see recent geological activity on a planet we often view as being “dead.”
This boulder (approximately 6 meters-wide) had come to a stop at the bottom of the sloping wall of an impact crater. The path the boulder took is obvious as it left a series of prints in the Martian regolith as it bounced and rolled. The darker material that appears to have flowed around the rock is relatively fresh dry dust and sand that has also been dislodged from the top of the slope, falling as an avalanche, settling as a dark streak. As time goes on, the streak will age and blend in with the surrounding regolith.
It is suspected that seismic activity or a weather event (such as a dust devil) may have triggered the avalanche. As for the boulder, it looks like it rolled down the slope before the sand/dust avalanche, so it may have originated from the same destabilization event, or it happened earlier. As the source of the streak and boulder appear to originate from the same location, I suspect the former might be the case.
Regardless, it goes to show Mars is still active, and the MRO is in the perfect location to capture the Red Planet proving that fact.
A little help here? Spirit has driven into soft ground, burying her wheels halfway. Engineers are working plans to extricate her. –A distress tweet from @MarsRovers
Now, she’s stuck in the Martian dirt after slipping backwards down a slope during a series of backward drives around a plateau called “Home Plate.”
“Spirit is in a very difficult situation,” JPL project manager John Callas said. “We are proceeding methodically and cautiously. It may be weeks before we try moving Spirit again. Meanwhile, we are using Spirit’s scientific instruments to learn more about the physical properties of the soil that is giving us trouble.”
At JPL, a team have been assembled to try to find a solution to the problem with a model of the situation here on Earth. Unfortunately the wheels are stuck fast, half-buried, and scientists are increasingly worried that any attempts to free the struggling rover could make matters worse. The concern is for the chassis under the robot. Should it make contact with the rocks underneath, it would effectively beach itself, completely losing traction that could be used to free the wheels. In short, the situation is not good, but NASA is working overtime to find ways to get the rover on the road once more.
Fortunately, wind has helped the ailing rover recently, clearing excess dust off the solar panels, giving Spirit a much needed energy boost, but will it be enough to get her out of this difficult situation? If there’s a way, Spirit will find it, as let’s face it, she’s lived through a lot of hard knocks…
This strange image was captured by the Mars Reconnaissance Orbiter’s (MRO) camera–the amazing High Resolution Imaging Science Experiment (HiRISE)–as it passed over one of the largest volcanoes in the Solar System, Pavonis Mons.
Located near the equator of Mars, atop the Tharsis bulge, Pavonis Mons is the second highest volcano after the huge Olympus Mons (towering over the Martian surface 27 km high). Pavonis Mons is still much higher than anything the Earth can muster, towering 14km into the atmosphere (compare that with the altitude of Mt. Everest’s peak height of 8.85 km).
So why is this picture so blurry? Is HiRISE suffering a malfunction? Did mission control send the wrong commands? Actually, HiRISE is working just fine. It’s the dust-covered surface that’s blurred.
As the ancient volcano is reaching so high into the Martian atmosphere, the air becomes very thin. The atmosphere was already thin; the average ground level atmospheric pressure is less than 1% of the Earth’s. At Pavonis Mons’ peak, the atmospheric pressure is ten-times thinner. Therefore any wind at these altitudes is extremely weak.
The extreme planet-wide dust storms that regularly engulf Mars dump huge quantities of dust on the top of the Martian volcanoes, but when the dust settles, there’s nothing to transport it elsewhere. Therefore, the thick layer of fine material remains where it is, tickled by the light-weight winds, rarely moving.
In the high resolution image, you can see some resolved features such as the odd impact crater and small ripples. Other than that, it’s a thick, smooth dust blanket that covers the Pavonis Mons summit, hiding any interesting geology for below, giving the impression any images of the summit are out of focus…